Inhibition of Colon Cancer Line Growth by Herbal Plants of the Ryukyu Islands

There is increasing interest in the use of herbal products to maintain human health. Plants contain a wide variety of compounds that may have biological activities including anticancer effect (Boik, 2001). There are many kinds of herbal plants in the Ryukyu Islands, Okinawa, Japan. Some of them have been used for the treatment of patients who are affected with insomnia, severe infections, or enterocolitis in Okinawa from ancient times. Especially in women, Okinawa is known as one of longevity areas in Japan (Planning and information section, 2001), and lower incidence of cancer may contribute longer life span (Planning and information section, 2001). In a recent study, we found that the herbs Peucedanum japonicum and Terminalia catuppa that are widely distributed in Eastern Asian counties including the Ryukyu Islands inhibit the occurrence of aberrant crypt foci (ACF), known as putative preneoplastic lesions in rat colon carcinogenesis (Morioka et al., 2004; Morioka et al., 2005). Although the above-described Growth Inhibitory Activities of Crude Extracts Obtained from Herbal Plants in the Ryukyu Islands on Several Human Colon Carcinoma Cell Lines